CVE-2026-43911Public exploitNetwork attack vector

Persistent vault access via omitted stamp validation

Published May 11, 2026 · Updated May 11, 2026

Insufficient session expiration in Vaultwarden before 1.35.5 allows remote authenticated users with refresh tokens to retain vault access. The refresh_tokens flow in src/auth.rs resolves only a Device by device_token; refresh claims omit the user's security_stamp and the flow never compares the current stamp, so tokens issued before rotation remain valid. Attackers must possess an active device's refresh token; after a password, KDF, key, email, administrative reset, or emergency takeover change, the token still allows reading and modifying vault entries.

CVSS severity6.8
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient session expiration in Vaultwarden before 1.35.5 allows remote authenticated users with refresh tokens to retain vault access. The refresh_tokens flow in src/auth.rs resolves only a Device by device_token; refresh claims omit the user's security_stamp and the flow never compares the current stamp, so tokens issued before rotation remain valid. Attackers must possess an active device's refresh token; after a password, KDF, key, email, administrative reset, or emergency takeover change, the token still allows reading and modifying vault entries.

The record

CVE
CVE-2026-43911
Published
May 11, 2026
Updated
May 11, 2026
Vendor
Dani Garcia
Product
Vaultwarden
Classifications
CWE-613, T1550.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 11, 2026CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.35.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Dani Garcia · Vaultwardenversion=< 1.35.5

Published CVSS scores

6.8GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
8.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-613Insufficient Session Expiration
T1550.001Use Alternate Authentication Material: Application Access Token

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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